vätehaliderna

Vätehaliderna, also known as hydrogen halides, are binary compounds of hydrogen and a halogen. The halogens are fluorine, chlorine, bromine, iodine, and astatine. These compounds are generally formed by direct reaction between hydrogen and the respective halogen element, although other synthesis methods exist. At room temperature, hydrogen fluoride (HF) is a liquid, while hydrogen chloride (HCl), hydrogen bromide (HBr), and hydrogen iodide (HI) are gases. Hydrogen astatide (HAt) is highly unstable and radioactive.

Hydrogen halides are acidic in aqueous solution due to their ability to donate a proton. Hydrogen fluoride is a weak acid, while hydrogen chloride, hydrogen bromide, and hydrogen iodide are strong acids. They are highly soluble in water, forming hydrohalic acids. These acids are important reagents in various chemical processes, including organic synthesis and industrial applications. For example, HCl is used in the production of PVC and in metal cleaning.

The reactivity of hydrogen halides varies. Hydrogen fluoride is highly corrosive and can etch glass, a property exploited in some industrial processes. The other hydrogen halides are strong reducing agents, with their reducing strength increasing down the group. Hydrogen iodide is the strongest reducing agent among them. The stability of these compounds also decreases down the group, with hydrogen astatide being the least stable. The properties and reactivity of hydrogen halides are of significant interest in inorganic and physical chemistry.